Delivery of the weight-loss injection Mounjaro has been paused in the UK as people rush to stockpile the drug before a price increase.
On Wednesday the US manufacturer of the drug, Eli Lilly, told its two British wholesalers to temporarily stop taking orders after demand soared before the price increase comes into force on September 1.
Eli Lilly is increasing the amount it charges pharmacies after a demand from President Trump that pharma firms stop allowing other countries to “freeload”. The rate for a 5mg dose, the third largest, will nearly double from £92 to £180 while the maximum dose, 15mg, will increase from £122 to £330.
Pharmacists warned that the move risked causing suffering to patients.
• Mounjaro weight-loss injections now available in UK through NHS
Dr Leyla Hannbeck, chief executive of the Independent Pharmacies Association, said: “It is completely unacceptable that Eli Lilly has not only decided to cause significant instability by increasing prices with minimal notice, but is now making matters worse by suspending supply until those higher prices take effect in September.
• Ozempic sales ‘rise by 500%’ after Mounjaro price hike announcement
“Patients will understandably be extremely concerned about their ability to access vital medication, and it will be pharmacists on the front line who are left to manage the fallout.
“Pharmacies across the country have already been extending opening hours to provide anxious patients the support they need. Lilly’s latest move is throwing the system into chaos.
“It is utterly wrong that patients are being made to suffer as a result of Eli Lilly’s pursuit of profit. There is still time for Eli Lilly to reverse this disastrous decision, and I sincerely urge them to do the right thing.”
A spokesman for Eli Lilly said: “The UK was one of the first countries where Lilly launched Mounjaro, and our priority was to bring it to patients as quickly as possible during a time of limited supply of GLP-1 RA treatments for type 2 diabetes.
“At launch, Lilly agreed to a UK list price that is significantly below the European average to prevent delays in NHS availability. With changes in the environment and clinical evidence supporting the value of Mounjaro, we are now aligning the list price more consistently to ensure fair global contributions to the cost of innovation.”
Pharmacists have also cautioned that more people could turn to the black market as a result of the increase.
About 18,300 illegal weight-loss and diabetes medications, including fake Ozempic and Mounjaro pens, were seized by Border Force at Heathrow between June 2024 and June 2025.
The data, obtained by the online pharmacy group Chemist4U using freedom of information laws, showed that smugglers had been stopped at the airport with fake Mounjaro pens hidden on their bodies.
Some of these items are being sold by unregulated online sellers and beauty clinics, who are seeking to make a quick profit from soaring demand for weight-loss medications. About 1.5 million people in the UK take Mounjaro or Wegovy, bought privately from online pharmacies.
Health regulators have warned fake injections could be dangerous and have fatal side-effects.
• Mounjaro UK price rise will trigger obesity relapse, say experts
Jason Murphy, a weight-loss injection specialist and Head of Pharmacy at Chemist4U, said: “Counterfeit medicines are a growing problem, and the surge in smuggled weight loss injections shows how criminals are exploiting rising demand.
“Fake pens aren’t just illegal, they could be contaminated, expired or completely ineffective. Our FOI data shows that the black market for weight loss injections is already thriving in the UK. Patients must be cautious. We urge them to only use regulated pharmacies to protect their health.”